U.S. patent number 10,897,602 [Application Number 16/511,006] was granted by the patent office on 2021-01-19 for projection display device for performing projection and imaging comprising optical image emitting light valve and imaging optical system.
This patent grant is currently assigned to FUJIFILM Corporation. The grantee listed for this patent is FUJIFILM Corporation. Invention is credited to Kazuki Inoue, Chikara Yamamoto.
![](/patent/grant/10897602/US10897602-20210119-D00000.png)
![](/patent/grant/10897602/US10897602-20210119-D00001.png)
![](/patent/grant/10897602/US10897602-20210119-D00002.png)
![](/patent/grant/10897602/US10897602-20210119-D00003.png)
![](/patent/grant/10897602/US10897602-20210119-D00004.png)
![](/patent/grant/10897602/US10897602-20210119-D00005.png)
![](/patent/grant/10897602/US10897602-20210119-D00006.png)
![](/patent/grant/10897602/US10897602-20210119-D00007.png)
United States Patent |
10,897,602 |
Inoue , et al. |
January 19, 2021 |
Projection display device for performing projection and imaging
comprising optical image emitting light valve and imaging optical
system
Abstract
A projection display device includes an imaging element, a light
source, a light valve that modulates light from the light source
and emits modulated light in a prescribed polarization state, and
an imaging optical system. The imaging optical system includes a
first optical system that is used in common in projection and
imaging, a second optical system that is used only in projection, a
third optical system that is used only in imaging, and a separation
member that separates an optical path from the second optical
system toward the first optical system from an optical path from
the first optical system toward the third optical system. The first
optical system comprises a quarter wave plate and a polarizer
arranged in a state of transmitting the light emitted from the
light valve.
Inventors: |
Inoue; Kazuki (Saitama,
JP), Yamamoto; Chikara (Saitama, JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
FUJIFILM Corporation |
Tokyo |
N/A |
JP |
|
|
Assignee: |
FUJIFILM Corporation (Tokyo,
JP)
|
Appl.
No.: |
16/511,006 |
Filed: |
July 15, 2019 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20200033702 A1 |
Jan 30, 2020 |
|
Foreign Application Priority Data
|
|
|
|
|
Jul 27, 2018 [JP] |
|
|
2018-141676 |
Feb 27, 2019 [JP] |
|
|
2019-034990 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G03B
21/28 (20130101); H04N 9/3176 (20130101); H04N
9/3194 (20130101); G03B 17/54 (20130101) |
Current International
Class: |
H04N
9/31 (20060101); G03B 17/54 (20060101); G03B
21/28 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Le; Bao-Luan Q
Attorney, Agent or Firm: Studebaker & Brackett PC
Claims
What is claimed is:
1. A projection display device comprising: an imaging element that
performs imaging with received light; a light valve that emits an
optical image based on image data in a prescribed polarization
state; and an imaging optical system that projects an optical image
of light emitted from the light valve onto a magnification side
imaging surface and forms an image of light incident from a
magnification side on the imaging element, wherein the imaging
optical system comprises a first optical system that comprises at
least one lens and is used in common in projection and imaging, a
second optical system that comprises at least one lens and is used
only in projection, a third optical system that comprises at least
one lens and is used only in imaging, and a separation member that
separates an optical path from the second optical system toward the
first optical system from an optical path from the first optical
system toward the third optical system, the first optical system
comprises, in order from the magnification side, a quarter wave
plate and a polarizer arranged in a state of transmitting the light
emitted from the light valve or the third optical system comprises
a polarizer arranged in a state of shielding the light emitted from
the light valve, and in a case where the first optical system
comprises the quarter wave plate and the polarizer, the quarter
wave plate and the polarizer are arranged on a most reduction side
in the first optical system on an optical path.
2. The projection display device according to claim 1, wherein an
extinction ratio of the polarizer is less than 0.1%.
3. The projection display device according to claim 1, wherein the
separation member is a reflective polarizer.
4. The projection display device according to claim 1, further
comprising: an adjustment mechanism that adjusts a transmission
axis direction of the polarizer comprised in the first optical
system or the polarizer comprised in the third optical system.
5. The projection display device according to claim 1, wherein, in
a case where the third optical system comprises the polarizer, the
polarizer is arranged on a most magnification side in the third
optical system on an optical path.
6. The projection display device according to claim 1, wherein the
second optical system comprises a polarizer arranged in a state of
transmitting the light emitted from the light valve.
7. The projection display device according to claim 6, further
comprising: an adjustment mechanism that adjusts a transmission
axis direction of the polarizer comprised in the second optical
system.
8. The projection display device according to claim 6, wherein the
polarizer comprised in the second optical system is arranged on a
most magnification side in the second optical system on an optical
path.
9. The projection display device according to claim 1, further
comprising: two or more polarizers between a lens of the first
optical system on a most reduction side on an optical path and the
imaging element.
10. The projection display device according to claim 1, wherein an
optical system consisting of the first optical system and the
second optical system to be used in projection is a relay optical
system that forms an intermediate image.
11. The projection display device according to claim 1, wherein an
optical system consisting of the first optical system and the third
optical system to be used in imaging is a relay optical system that
forms an intermediate image.
12. The projection display device according to claim 10, wherein
the separation member is arranged to be closer to the magnification
side than the intermediate image on an optical path.
13. A projection display device comprising: an imaging element that
performs imaging with received light; a light valve that emits an
optical image based on image data; and an imaging optical system
that projects an optical image of light emitted from the light
valve onto a magnification side imaging surface and forms an image
of light incident from a magnification side on the imaging element,
wherein the imaging optical system comprises a first optical system
that comprises at least one lens and is used in common in
projection and imaging, a second optical system that comprises at
least one lens and is used only in projection, a third optical
system that comprises at least one lens and is used only in
imaging, and a separation member that is transflective and
separates an optical path from the second optical system toward the
first optical system from an optical path from the first optical
system toward the third optical system, the separation member is
arranged on a most magnification side among reflection members in
the imaging optical system, and an optical system consisting of the
first optical system and the third optical system to be used in
imaging is a relay optical system that forms an intermediate
image.
14. The projection display device according to claim 13, wherein
the separation member is arranged in a state of reflecting light on
the optical path from the second optical system toward the first
optical system and transmitting light on the optical path from the
first optical system toward the third optical system.
15. The projection display device according to claim 14, wherein
the separation member has a transflective reflective film that is
formed on one surface of a transparent substrate and faces the
first optical system, and is arranged in a state of reflecting
light on the optical path from the second optical system toward the
first optical system and transmitting light on the optical path
from the first optical system toward the third optical system.
16. The projection display device according to claim 13, wherein an
optical system consisting of the first optical system and the
second optical system to be used in projection is a relay optical
system that forms an intermediate image.
17. The projection display device according to claim 16, wherein
the separation member is arranged to be closer to the magnification
side than the intermediate image on an optical path.
18. A projection display device comprising: an imaging element that
performs imaging with received light; a light valve that emits an
optical image based on image data in a prescribed polarization
state; an imaging optical system that projects an optical image of
light emitted from the light valve onto a magnification side
imaging surface and forms an image of light incident from a
magnification side on the imaging element; and an adjustment
mechanism that adjusts a transmission axis direction of the
polarizer comprised in the first optical system or the polarizer
comprised in the third optical system, wherein the imaging optical
system comprises a first optical system that comprises at least one
lens and is used in common in projection and imaging, a second
optical system that comprises at least one lens and is used only in
projection, a third optical system that comprises at least one lens
and is used only in imaging, and a separation member that separates
an optical path from the second optical system toward the first
optical system from an optical path from the first optical system
toward the third optical system, and the first optical system
comprises, in order from the magnification side, a quarter wave
plate and a polarizer arranged in a state of transmitting the light
emitted from the light valve or the third optical system comprises
a polarizer arranged in a state of shielding the light emitted from
the light valve.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
The present application claims priority under 35 U.S.C. .sctn. 119
to Japanese Patent Application No. 2018-141676 filed on Jul. 27,
2018, and Japanese Patent Application No. 2019-034990 filed on Feb.
27, 2019. The above applications are hereby expressly incorporated
by reference, in its entirety, into the present application.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present disclosure relates to a projection display device.
2. Description of the Related Art
In recent years, a projection display device that comprises a light
valve, such as a liquid crystal display element or a liquid crystal
on silicon (LCOS) display element, comprises an imaging element,
such as a charge coupled device (CCD) or a complementary metal
oxide semiconductor (CMOS), and can perform both of projection and
imaging has been suggested (for example, WO2017/014317).
SUMMARY OF THE INVENTION
The projection display device of WO2017/014317 comprises a
separation member that separates an optical path from a light valve
toward a screen from an optical path from a magnification side
(screen side) toward an imaging element, and is configured such
that a part of an imaging optical system in the projection display
device is used in common at the time of projection and at the time
of imaging.
However, in the projection display device of WO2017/014317, there
is a concern that a part of light emitted from the light valve
leaks to the imaging element side due to the performance of the
separation member. Since light emitted from the light valve has
high brightness to be projected onto the screen, in a case where
light with high brightness leaks from the light valve to the
imaging element side, leakage causes deterioration of imaging
quality, such as occurrence of strong ghost in a captured
image.
The present disclosure has been accomplished in consideration of
the above-described situation, and an object of the present
disclosure is to provide a projection display device capable of
performing both of projection and imaging, and suppressing
deterioration of imaging quality.
Specific means for solving the above-described problem include the
following aspects.
<1> A projection display device comprising an imaging element
that performs imaging with received light, a light valve that emits
an optical image based on image data in a prescribed polarization
state, and an imaging optical system that projects an optical image
of light emitted from the light valve onto a magnification side
imaging surface and forms an image of light incident from a
magnification side on the imaging element, in which the imaging
optical system comprises a first optical system that comprises at
least one lens and is used in common in projection and imaging, a
second optical system that comprises at least one lens and is used
only in projection, a third optical system that comprises at least
one lens and is used only in imaging, and a separation member that
separates an optical path from the second optical system toward the
first optical system from an optical path from the first optical
system toward the third optical system, and the first optical
system comprises, in order from the magnification side, a quarter
wave plate and a polarizer arranged in a state of transmitting the
light emitted from the light valve or the third optical system
comprises a polarizer arranged in a state of shielding the light
emitted from the light valve.
<2> The projection display device of <1>, in which an
extinction ratio of the polarizer is less than 0.1%. Here, the
"extinction ratio" means a transmittance ratio of light in a
direction perpendicular to a transmission axis to light in a
transmission axis direction.
<3> The projection display device of <1> or <2>,
in which, in a case where the first optical system comprises the
quarter wave plate and the polarizer, the quarter wave plate and
the polarizer are arranged on a most reduction side in the first
optical system on an optical path.
<4> The projection display device of any one of <1> to
<3>, in which the separation member is a reflective
polarizer.
<5> The projection display device of any one of <1> to
<4>, further comprising an adjustment mechanism that adjusts
a transmission axis direction of the polarizer comprised in the
first optical system or the polarizer comprised in the third
optical system.
<6> The projection display device of any one of <1> to
<5>, in which, in a case where the third optical system
comprises the polarizer, the polarizer is arranged on a most
magnification side in the third optical system on an optical
path.
<7> The projection display device of any one of <1> to
<6>, in which the second optical system comprises a polarizer
arranged in a state of transmitting the light emitted from the
light valve.
<8> The projection display device of <7>, further
comprising an adjustment mechanism that adjusts a transmission axis
direction of the polarizer comprised in the second optical
system.
<9> The projection display device of <7> or <8>,
in which the polarizer comprised in the second optical system is
arranged on a most magnification side in the second optical system
on an optical path.
<10> The projection display device of any one of <1> to
<9>, further comprising two or more polarizers between a lens
of the first optical system on a most reduction side on an optical
path and the imaging element.
<11> The projection display device of any one of <1> to
<10>, in which an optical system consisting of the first
optical system and the second optical system to be used in
projection is a relay optical system that forms an intermediate
image.
<12> The projection display device of any one of <1> to
<11>, in which an optical system consisting of the first
optical system and the third optical system to be used in imaging
is a relay optical system that forms an intermediate image.
<13> The projection display device of <11> or
<12>, in which the separation member is arranged to be closer
to the magnification side than the intermediate image on an optical
path.
<14> A projection display device comprising an imaging
element that performs imaging with received light, a light valve
that emits an optical image based on image data, and an imaging
optical system that projects an optical image of light emitted from
the light valve onto a magnification side imaging surface and forms
an image of light incident from a magnification side on the imaging
element, in which the imaging optical system comprises a first
optical system that comprises at least one lens and is used in
common in projection and imaging, a second optical system that
comprises at least one lens and is used only in projection, a third
optical system that comprises at least one lens and is used only in
imaging, and a separation member that is transflective and
separates an optical path from the second optical system toward the
first optical system from an optical path from the first optical
system toward the third optical system, and the separation member
is arranged on a most magnification side among reflection members
in the imaging optical system.
<15> The projection display device of <14>, in which
the separation member is arranged in a state of reflecting light on
the optical path from the second optical system toward the first
optical system and transmitting light on the optical path from the
first optical system toward the third optical system.
<16> The projection display device of <15>, in which
the separation member has a transflective reflective film that is
formed on one surface of a transparent substrate and faces the
first optical system, and is arranged in a state of reflecting
light on the optical path from the second optical system toward the
first optical system and transmitting light on the optical path
from the first optical system toward the third optical system.
<17> The projection display device of any one of <14>
to <16>, in which an optical system consisting of the first
optical system and the second optical system to be used in
projection is a relay optical system that forms an intermediate
image.
<18> The projection display device of any one of <14>
to <17>, in which an optical system consisting of the first
optical system and the third optical system to be used in imaging
is a relay optical system that forms an intermediate image.
<19> The projection display device of <17> or
<18>, in which the separation member is arranged to be closer
to the magnification side than the intermediate image on an optical
path.
According to the present disclosure, it is possible to provide a
projection display device capable of suppressing deterioration of
imaging quality.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic configuration diagram of a projection display
device according to a first embodiment of the invention.
FIG. 2 is a schematic configuration diagram of a projection display
device according to a second embodiment of the invention.
FIG. 3 is a schematic configuration diagram of a projection display
device according to a third embodiment of the invention.
FIG. 4 is a schematic configuration diagram of a projection display
device according to a fourth embodiment of the invention.
FIG. 5 is a schematic configuration diagram of a projection display
device according to a fifth embodiment of the invention.
FIG. 6 is a schematic configuration diagram of a projection display
device according to a sixth embodiment of the invention.
FIG. 7 is a schematic configuration diagram of a projection display
device according to a seventh embodiment of the invention.
FIG. 8 is a schematic configuration diagram of a projection display
device according to an eighth embodiment of the invention.
FIG. 9 is a schematic configuration diagram of a projection display
device according to a ninth embodiment of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Hereinafter, a first embodiment of a projection display device of
the invention will be described in detail referring to the
drawings. FIG. 1 is a schematic configuration diagram of a
projection display device according to the first embodiment of the
invention. In FIG. 1, a screen 12 side becomes a magnification side
in an optical path order.
As shown in FIG. 1, a projection display device 1 of the embodiment
comprises an imaging element 10 that performs imaging with received
light, an image projection unit 11 that consists of a light source
and a light valve, and an imaging optical system that projects an
optical image of light optically modulated by the light valve onto
a screen (magnification side imaging surface) 12 and forms an image
of light incident from the magnification side on the imaging
element.
The light valve modulates light from the light source and emits
modulated light in a prescribed polarization state. As an image
display element that is used for the light valve, any image display
element, such as a liquid crystal display element or a liquid
crystal on silicon (LCOS) display element, may be used. The light
source may be appropriately composed corresponding to a system of
the image display element of the light valve.
The imaging optical system comprises a first optical system G1 that
comprises at least one lens and is used in common in projection and
imaging, a second optical system G2 that comprises at least one
lens and is used only in projection, a third optical system G3 that
comprises at least one lens and is used only in imaging, and a
separation member S that separates an optical path from the second
optical system G2 toward the first optical system G1 from an
optical path from the first optical system G1 toward the third
optical system G3.
The first optical system G1 comprises, in order from the
magnification side on the optical path, a lens group L1, a quarter
wave plate W, and a polarizer P arranged in a state of transmitting
light emitted from the light valve.
The second optical system G2 comprises, in order from the
magnification side on the optical path, a lens group L2a, a lens
group L2b, a reflection member R, a lens group L2c, and an optical
member PP assumed to be a filter, a prism, or the like that is used
in a color synthesis unit or an illumination light separation
unit.
The third optical system G3 comprises a lens group L3.
Each lens group in the first optical system G1, the second optical
system G2, and the third optical system G3 is not limited to a
configuration in which the lens group consists of a plurality of
lenses, and may have a configuration in which the lens group
consists of only one lens.
The separation member S reflects light from the second optical
system G2 toward the first optical system G1 and transmits light
from the first optical system G1 toward the third optical system
G3, and is composed of, for example, a transflective member, such
as a half mirror.
The imaging optical system is composed as described above, whereby
it is possible to secure the number of lenses (the lenses of the
first optical system G1 and the second optical system G2) to be
used in projection to provide high projection performance while
suppressing the number of lenses of the first optical system G1 to
be used in common in projection and imaging. Similarly, it is
possible to secure the number of lenses (the lenses of the first
optical system G1 and the third optical system G3) to be used in
imaging to provide high imaging performance.
The number of lenses (the lenses of the first optical system G1) to
be used in projection among the lenses (the lenses of the first
optical system G1 and the third optical system G3) to be used in
imaging is reduced, and the number of reflective surfaces of
projection light decreases. For this reason, it is possible to
suppress reflected ghost.
In addition, the quarter wave plate W and the polarizer P arranged
in a state of transmitting light (projection light) emitted from
the light valve are comprised in the first optical system G1,
whereby it is possible to further reduce reflected light of
projection light incident from the first optical system G1 on the
third optical system G3.
An operation will be described specifically. As an example, a case
where linearly polarized projection light is emitted from the image
projection unit 11 will be described. Projection light emitted from
the light valve in a linearly polarized state (for example, a
vertical direction in the drawing) is transmitted through the
polarizer P, and is converted to a circularly polarized state (for
example, a right-handed circularly polarized state) when
transmitted through the quarter wave plate W. Then, in a case where
projection light in the circularly polarized state (for example,
the right-handed circularly polarized state) is reflected by the
lens group L1, a rotation direction of circularly polarized light
is reversed.
Reflected light in the reversed circularly polarized state (for
example, a left-handed circularly polarized state) is converted to
a linearly polarized state (for example, a horizontal direction in
the drawing) when transmitted through the quarter wave plate W
again; however, since the direction of linearly polarized light at
this time is rotated by 90.degree. compared to when light is
emitted from the light valve, light cannot be transmitted through
the polarizer P. Accordingly, it is possible to reduce reflected
light of projection light incident from the first optical system G1
on the third optical system G3.
On the other hand, since light incident from the magnification side
of the first optical system G1 at the time of imaging is in a
non-polarization state and includes light in all vibration
directions, a part of light is transmitted through the polarizer P
and is incident on the third optical system G3. Accordingly, it is
possible to perform imaging without any troubles.
Since it is assumed that the screen 12 has a matte surface suitable
for projecting video, video projected from the image projection
unit 11 onto the screen 12 has no polarization state by so-called
Lambertian reflectance. For this reason, even for video projected
onto the screen 12, it is possible to perform imaging without any
troubles.
In the projection display device 1 of the embodiment, in a case of
reducing reflected light of projection light incident from the
first optical system G1 on the third optical system G3, the
reduction amount of reflected light depends on the performance of
the polarizer P. For this reason, the extinction ratio of the
polarizer is less than 0.1%, whereby it is possible to sufficiently
reduce reflected light of projection light incident from the first
optical system G1 on the third optical system G3.
It is preferable that, in a case where the quarter wave plate W and
the polarizer P are comprised in the first optical system G1, the
quarter wave plate W and the polarizer P are arranged on a most
reduction side in the first optical system G1 on the optical path.
With such a configuration, it is possible to increase an effect in
a case of reducing reflected light of projection light incident
from the first optical system G1 on the third optical system
G3.
It is preferable that an adjustment mechanism that adjusts the
transmission axis direction of the polarizer P is comprised. For
example, in a case where relative position fluctuation between the
image projection unit 11 and each optical element composing the
imaging optical system occurs due to change in temperature,
deformation, or the like, it is not possible to precisely control
light to be transmitted or shielded in the light polarizer P. For
this reason, the above-described adjustment mechanism is comprised,
whereby it is possible to precisely control light to be transmitted
or shielded in the polarizer P even in a case where the relative
position fluctuation between the image projection unit 11 and each
optical element composing the imaging optical system occurs.
The adjustment of the transmission axis direction of the polarizer
P with the adjustment mechanism may be performed manually or may be
performed automatically in combination with various sensors. In a
case where the adjustment is performed automatically, for example,
a sensor that detects the relative position fluctuation between the
image projection unit 11 and each optical element composing the
imaging optical system may be provided, and the transmission axis
direction of the polarizer P may be adjusted based on the relative
position fluctuation. Alternatively, light of a predetermined
amount may be projected from the image projection unit 11, and the
transmission axis direction of the polarizer P may be adjusted such
that the amount of light detected by the imaging element 10 becomes
a reference value (for example, a value in a case where there is no
relative position fluctuation).
It is preferable that an optical system consisting of the first
optical system G1 and the second optical system G2 to be used in
projection is a relay optical system that forms an intermediate
image MI. With such a configuration, it is possible to achieve a
wide angle with one eye. Furthermore, an optical system to be used
in projection is composed of a relay optical system, a reflection
member that bends the optical path is easily inserted into the
optical system, and a light beam on the projection display device
side in projection light emitted from the projection display device
can approach a horizontal state to a housing of the projection
display device. For this reason, it is possible to improve the
installability of the projection display device.
In this case, the separation member S is arranged to be closer to
the magnification side than the intermediate image MI on the
optical path. With such a configuration, the number of lenses (the
lenses of the first optical system G1) to be used in projection
among the lenses (the lenses of the first optical system G1 and the
third optical system G3) to be used in imaging is reduced, and the
number of reflective surfaces of projection light decreases. For
this reason, it is possible to suppress reflected ghost.
Even an optical system consisting of the first optical system G1
and the third optical system G3 to be used in imaging may be
composed of a relay optical system that forms an intermediate
image. With such a configuration, it is possible to achieve a wide
angle with one eye. The optical system to be used in imaging is
composed of a relay optical system, whereby a reflection member
that bands the optical path is easily inserted into the third
optical system G3. For this reason, even in a case where the third
optical system G3 is designed with high performance to comprise
multiple lenses, it is possible to suppress the total length of the
third optical system G3. Therefore, it is possible to achieve both
of performance and reduction in size of the projection display
device.
Next, a second embodiment of a projection display device of the
invention will be described in detail referring to the drawings.
FIG. 2 is a schematic configuration diagram of a projection display
device according to the second embodiment of the invention. In FIG.
2, the screen 12 side becomes the magnification side in the optical
path order. In the embodiment, elements similar to the elements in
FIG. 1 are represented by the same reference numerals and
description thereof will not be repeated unless needed. Here, only
a difference will be primarily described.
As shown in FIG. 2, a projection display device 2 of the embodiment
is different from the projection display device 1 of the first
embodiment in that a polarizer P2 is added on the most
magnification side in the third optical system G3. The polarizer P2
is arranged such that a transmission axis direction of the
polarizer P2 becomes the same direction as a transmission axis
direction of a polarizer P1 (the polarizer P in FIG. 1).
Even in the projection display device 2 of the embodiment, it is
possible to obtain the same effects as the projection display
device 1 of the first embodiment. In addition, since the two
polarizers P1 and P2 are comprised between a lens of the first
optical system G1 on a most reduction side on the optical path to
the imaging element 10, the extinction ratio of the entire
polarizer portion decreases, and it is possible to further reduce
reflected light of projection light incident from the first optical
system G1 on the third optical system G3.
Next, a third embodiment of a projection display device of the
invention will be described in detail referring to the drawings.
FIG. 3 is a schematic configuration diagram of a projection display
device according to the third embodiment of the invention. In FIG.
3, the screen 12 side becomes the magnification side in the optical
path order. In the embodiment, elements similar to the elements in
FIG. 1 are represented by the same reference numerals and
description thereof will not be repeated unless needed. Here, only
a difference will be primarily described.
A projection display device 3 of the embodiment has the
configuration of the imaging optical system different from the
projection display device 1 of the first embodiment. As shown in
FIG. 3, the imaging optical system of the projection display device
3 of the embodiment comprises a first optical system G1 that
comprises at least one lens and is used in common in projection and
imaging, a second optical system G2 that comprises at least one
lens and is used only in projection, a third optical system G3 that
comprises at least one lens and is used only in imaging, and a
separation member S that separates an optical path from the second
optical system G2 toward the first optical system G1 from an
optical path from the first optical system G1 toward the third
optical system G3.
The first optical system G1 comprises, in order from the
magnification side on an optical path, a lens group L1a, a
reflection member R1, a lens group L1b, and a lens group L1c.
The second optical system G2 comprises, in order from the
magnification side on an optical path, a lens group L2, and an
optical member PP assumed to be a filter, a prism, or the like that
is used in a color synthesis unit or an illumination light
separation unit.
The third optical system G3 comprises, in order from the
magnification side on the optical path, a reflection member R2, a
polarizer P arranged in a state of shielding light emitted from the
light valve, and a lens group L3.
The separation member S reflects light from the second optical
system G2 toward the first optical system G1 and transmits light
from the first optical system G1 toward the third optical system
G3, and is composed of, for example, a transflective member, such
as a half mirror.
The imaging optical system is composed as described above, whereby
it is possible to secure the number of lenses (the lenses of the
first optical system G1 and the second optical system G2) to be
used in projection to provide high projection performance while
suppressing the number of lenses of the first optical system G1 to
be used in common in projection and imaging. Similarly, it is
possible to secure the number of lenses (the lenses of the first
optical system G1 and the third optical system G3) to be used in
imaging to provide high imaging performance.
The number of lenses (the lenses of the first optical system G1) to
be used in projection among the lenses (the lenses of the first
optical system G1 and the third optical system G3) to be used in
imaging is reduced, and the number of reflective surfaces of
projection light decreases. For this reason, it is possible to
suppress reflected ghost.
The polarizer P arranged in a state of shielding light (projection
light) emitted from the light valve is comprised in the third
optical system G3, whereby it is possible to reduce projection
light incident from the second optical system G2 on the third
optical system G3 and reflected light of projection light incident
from the first optical system G1 into the third optical system
G3.
An operation will be described specifically. As an example, a case
where a linear polarizer is used for the polarizer P will be
described. While projection light emitted from the light valve in a
predetermined polarization state passes the second optical system
G2 and is reflected to the first optical system G1 side by the
separation member S, a part of light may leak to the third optical
system G3 side.
Projection light incident from the second optical system G2 on the
third optical system G3 is incident on the polarizer P by way of
the reflection member R2; however, since the polarizer P is
arranged in a state of shielding light emitted from the light
valve, light cannot be transmitted through the polarizer P.
Accordingly, it is possible to reduce projection light incident
from the second optical system G2 on the third optical system
G3.
For reflected light of projection light incident from the first
optical system G1 on the third optical system G3, in a case where
light emitted from the light valve is linearly polarized light, a
polarization direction is not changed compared to when light is
emitted from the light valve. Furthermore, for reflected light of
projection light incident from the first optical system G1 on the
third optical system G3, in a case where light emitted from the
light valve is circularly polarized light, a rotation direction of
polarized light is reversed compared to when light is emitted from
the light valve, but it is the same that polarized light is
circularly polarized light. For this reason, reflected light of
projection light incident from the first optical system G1 on the
third optical system G3 is incident on the polarizer P by way of
the reflection member R2; however, since the polarizer P is
arranged in a state of shielding light emitted from the light
valve, light cannot be transmitted through the polarizer P.
Accordingly, it is possible to reduce reflected light of projection
light incident from the first optical system G1 into the third
optical system G3.
On the other hand, since light incident from the magnification side
of the first optical system G1 at the time of imaging is in a
non-polarization state and includes light in all vibration
directions, a part of light is transmitted through the polarizer P
and is incident on the third optical system G3. Accordingly, it is
possible to perform imaging without any troubles.
Since it is assumed that the screen 12 has a matte surface suitable
for projecting video, video projected from the image projection
unit 11 onto the screen 12 has no polarization state by so-called
Lambertian reflectance. For this reason, even for video projected
onto the screen 12, it is possible to perform imaging without any
troubles.
It is preferable that a projection display device 3 of the
embodiment comprises an adjustment mechanism that adjusts the
transmission axis direction of the polarizer P. For example, in a
case where the relative position fluctuation between the image
projection unit 11 and each optical element composing the imaging
optical system occurs due to change in temperature, deformation, or
the like, it is not possible to precisely control light to be
transmitted or shielded in the light polarizer P. For this reason,
the above-described adjustment mechanism is comprised, whereby it
is possible to precisely control light to be transmitted or
shielded in the polarizer P even in a case where the relative
position fluctuation between the image projection unit 11 and each
optical element composing the imaging optical system occurs.
The adjustment of the transmission axis direction of the polarizer
P with the adjustment mechanism may be performed manually or may be
performed automatically in combination with various sensors. In a
case where the adjustment is performed automatically, for example,
a sensor that detects the relative position fluctuation between the
image projection unit 11 and each optical element composing the
imaging optical system may be provided, and the transmission axis
direction of the polarizer P may be adjusted based on the relative
position fluctuation. Alternatively, light of a predetermined
amount may be projected from the image projection unit 11, and the
transmission axis direction of the polarizer P may be adjusted such
that the amount of light detected by the imaging element 10 becomes
a reference value (for example, a value in a case where there is no
relative position fluctuation).
It is preferable that, in a case where the polarizer P is comprised
in the third optical system G3, the polarizer P is arranged on the
most magnification side in the third optical system G3 on the
optical path. With such a configuration, it is possible to
eliminate the influence of polarization revolution in the third
optical system G3.
It is preferable that an optical system consisting of the first
optical system G1 and the second optical system G2 to be used in
projection is a relay optical system that forms an intermediate
image MI. With such a configuration, it is possible to achieve a
wide angle with one eye. Furthermore, an optical system to be used
in projection is composed of a relay optical system, a reflection
member that bends the optical path is easily inserted into the
optical system, and a light beam on the projection display device
side in projection light emitted from the projection display device
can approach a horizontal state to a housing of the projection
display device. For this reason, it is possible to improve the
installability of the projection display device.
Next, a fourth embodiment of a projection display device of the
invention will be described in detail referring to the drawings.
FIG. 4 is a schematic configuration diagram of a projection display
device according to the fourth embodiment of the invention. In FIG.
4, the screen 12 side becomes the magnification side in the optical
path order. In the embodiment, elements similar to the elements in
FIG. 1 are represented by the same reference numerals and
description thereof will not be repeated unless needed. Here, only
a difference will be primarily described.
A projection display device 4 of the embodiment has the
configuration of the imaging optical system different from the
projection display device 3 of the third embodiment. As shown in
FIG. 4, the imaging optical system of the projection display device
4 of the embodiment comprises a first optical system G1 that
comprises at least one lens and is used in common in projection and
imaging, a second optical system G2 that comprises at least one
lens and is used only in projection, a third optical system G3 that
comprises at least one lens and is used only in imaging, and a
separation member S that separates an optical path from the second
optical system G2 toward the first optical system G1 from an
optical path from the first optical system G1 toward the third
optical system G3.
The first optical system G1 comprises a lens group L1.
The second optical system G2 comprises, in order from the
magnification side on the optical path, a lens group L2a, a lens
group L2b, a reflection member R, a lens group L2c, and an optical
member PP assumed to be a filter, a prism, or the like that is used
in a color synthesis unit or an illumination light separation
unit.
The third optical system G3 comprises, in order from the
magnification side on the optical path, a polarizer P arranged in a
state of shielding light emitted from the light valve and a lens
group L3.
The separation member S reflects light from the second optical
system G2 toward the first optical system G1 and transmits light
from the first optical system G1 toward the third optical system
G3, and is composed of, for example, a transflective member, such
as a half mirror.
Even in the projection display device 4 of the embodiment, it is
possible to obtain the same effects as the projection display
device 3 of the third embodiment. In addition, since the separation
member S is arranged to be closer to the magnification side than
the intermediate image MI on the optical path, the number of lenses
(the lenses of the first optical system G1) to be used in
projection among the lenses (the lenses of the first optical system
G1 and the third optical system G3) to be used in imaging is
reduced, and the number of reflective surfaces of projection light
decreases. For this reason, it is possible to suppress reflected
ghost.
Next, a fifth embodiment of a projection display device of the
invention will be described in detail referring to the drawings.
FIG. 5 is a schematic configuration diagram of a projection display
device according to the fifth embodiment of the invention. In FIG.
5, the screen 12 side becomes the magnification side in the optical
path order. In the embodiment, elements similar to the elements in
FIG. 1 are represented by the same reference numerals and
description thereof will not be repeated unless needed. Here, only
a difference will be primarily described.
A projection display device 5 of the embodiment has the
configuration of the imaging optical system different from the
projection display device 1 of the first embodiment. As shown in
FIG. 5, the imaging optical system of the projection display device
5 of the embodiment comprises a first optical system G1 that
comprises at least one lens and is used in common in projection and
imaging, a second optical system G2 that comprises at least one
lens and is used only in projection, a third optical system G3 that
comprises at least one lens and is used only in imaging, and a
separation member SP that separates an optical path from the second
optical system G2 toward the first optical system G1 from an
optical path from the first optical system G1 toward the third
optical system G3.
The first optical system G1 comprises a lens group L1.
The second optical system G2 comprises, in order from the
magnification side on the optical path, a polarizer P1 arranged in
a state of transmitting light emitted from the light valve, a lens
group L2a, a lens group L2b, a reflection member R, a lens group
L2c, and an optical member PP assumed to be a filter, a prism, or
the like that is used in a color synthesis unit or an illumination
light separation unit.
The third optical system G3 comprises, in order from the
magnification side on the optical path, a polarizer P2 arranged in
a state of shielding light (projection light) emitted from the
light valve and a lens group L3.
The separation member SP reflects light from the second optical
system G2 toward the first optical system G1 and transmits light
from the first optical system G1 toward the third optical system
G3, and is composed of a reflective polarizer.
The imaging optical system is composed as described above, whereby
it is possible to secure the number of lenses (the lenses of the
first optical system G1 and the second optical system G2) to be
used in projection to provide high projection performance while
suppressing the number of lenses of the first optical system G1 to
be used in common in projection and imaging. Similarly, it is
possible to secure the number of lenses (the lenses of the first
optical system G1 and the third optical system G3) to be used in
imaging to provide high imaging performance.
The number of lenses (the lenses of the first optical system G1) to
be used in projection among the lenses (the lenses of the first
optical system G1 and the third optical system G3) to be used in
imaging is reduced, and the number of reflective surfaces of
projection light decreases. For this reason, it is possible to
suppress reflected ghost.
The polarizer P1 arranged in a state of transmitting light emitted
from the light valve is provided in the second optical system G2,
whereby the extinction ratio of the entire polarizer portion
decreases, and it is possible to reduce projection light and
reflected light of projection light incident on the third optical
system G3.
The polarizer P arranged in a state of shielding light (projection
light) emitted from the light valve is comprised in the third
optical system G3, whereby it is possible to reduce projection
light incident from the second optical system G2 on the third
optical system G3 and reflected light of projection light incident
from the first optical system G1 into the third optical system
G3.
In addition, the separation member SP is composed of a reflective
polarizer, whereby the extinction ratio of the entire polarizer
portion decreases, and it is possible to further reduce reflected
light of projection light incident from the first optical system G1
on the third optical system G3.
An operation will be described specifically. As an example, a case
where linearly polarized projection light is emitted from the image
projection unit 11 will be described. Projection light emitted from
the light valve in a linearly polarized state (for example, a
vertical direction in the drawing) is transmitted through the
polarizer P1, whereby light resolved from a polarization state when
emitted from the light valve is eliminated, and only light in a
polarization state when emitted from the light valve is reflected
to the first optical system G1 side by the separation member
(reflective polarizer) SP.
At this time, a part of light may leak to the third optical system
G3 side; however, since the polarizer P2 is arranged in a state of
shielding light emitted from the light valve, light cannot be
transmitted through the polarizer P2. Accordingly, it is possible
to reduce projection light incident from the second optical system
G2 into the third optical system G3.
For reflected light of projection light in the first optical system
G1, since light emitted from the light valve is linearly polarized
light, a polarization direction of light is not changed compared to
when light is emitted from the light valve. For this reason,
reflected light of projection light in the first optical system G1
is reflected to the second optical system G2 by the separation
member (reflective polarizer) SP. Accordingly, it is possible to
reduce reflected light of projection light incident from the first
optical system G1 into the third optical system G3.
On the other hand, since light incident from the magnification side
of the first optical system G1 at the time of imaging is in a
non-polarization state and includes light in all vibration
directions, a part of light (for example, light, the direction of
linear polarization of which is rotated by 90.degree. compared to
when light is emitted from the light valve) is transmitted through
separation member (reflective polarizer) SP and the polarizer P2,
and is incident on the third optical system G3. Accordingly, it is
possible to perform imaging without any troubles.
Since it is assumed that the screen 12 has a matte surface suitable
for projecting video, video projected from the image projection
unit 11 onto the screen 12 has no polarization state by so-called
Lambertian reflectance. For this reason, even for video projected
onto the screen 12, it is possible to perform imaging without any
troubles.
It is preferable that the projection display device 5 of the
embodiment comprises an adjustment mechanism that adjusts the
transmission axis direction of the polarizer P1. Such an adjustment
mechanism is comprised, whereby it is possible to precisely control
light to be transmitted or shielded in the polarizer P1 even in a
case where the relative position fluctuation between the image
projection unit 11 and each optical element composing the imaging
optical system occurs.
It is preferable that the polarizer P1 comprised in the second
optical system G2 is arranged on the most magnification side in the
second optical system G2 on the optical path. With such a
configuration, it is possible to eliminate the influence of
polarization revolution in the second optical system G2.
It is preferable that an optical system consisting of the first
optical system G1 and the second optical system G2 to be used in
projection is a relay optical system that forms an intermediate
image MI. With such a configuration, it is possible to achieve a
wide angle with one eye. Furthermore, an optical system to be used
in projection is composed of a relay optical system, a reflection
member that bends the optical path is easily inserted into the
optical system, and a light beam on the projection display device
side in projection light emitted from the projection display device
can approach a horizontal state to a housing of the projection
display device. For this reason, it is possible to improve the
installability of the projection display device.
In this case, it is preferable that the separation member
(reflective polarizer) SP is arranged to be closer to the
magnification side than the intermediate image MI on the optical
path. With such a configuration, the number of lenses (the lenses
of the first optical system G1) to be used in projection among the
lenses (the lenses of the first optical system G1 and the third
optical system G3) to be used in imaging is reduced, and the number
of reflective surfaces of projection light decreases. For this
reason, it is possible to suppress reflected ghost.
Next, a sixth embodiment of a projection display device of the
invention will be described in detail referring to the drawings.
FIG. 6 is a schematic configuration diagram of a projection display
device according to the sixth embodiment of the invention. In FIG.
6, the screen 12 side becomes the magnification side in the optical
path order. In the embodiment, elements similar to the elements in
FIG. 1 are represented by the same reference numerals and
description thereof will not be repeated unless needed. Here, only
a difference will be primarily described.
As shown in FIG. 6, while a projection display device 6 of the
embodiment has the configuration of a second optical system G2
slightly different from the projection display device 5 of the
fifth embodiment, the positions of the second optical system G2 and
the third optical system G3 with respect to the separation member
SP are changed.
The second optical system G2 of the embodiment comprises, in order
from the magnification side on the optical path, a polarizer P1
arranged in a state of transmitting light emitted from the light
valve, a lens group L2, and an optical member PP assumed to be a
filter, a prism, or the like that is used in a color synthesis unit
or an illumination light separation unit.
The separation member SP transmits light from the second optical
system G2 toward the first optical system G1 and reflects light
from the first optical system G1 toward the third optical system
G3.
Even in the projection display device 6 of the embodiment, it is
possible to obtain the same effects as the projection display
device 5 of the fifth embodiment.
Next, a seventh embodiment of a projection display device of the
invention will be described in detail referring to the drawings.
FIG. 7 is a schematic configuration diagram of a projection display
device according to the seventh embodiment of the invention. In
FIG. 7, the screen 12 side becomes the magnification side in the
optical path order.
As shown in FIG. 7, a projection display device 7 of the embodiment
comprises an imaging element 10 that performs imaging with received
light, an image projection unit 11 consisting of a light source and
a light valve, and an imaging optical system that projects an
optical image of light optically modulated by the light valve onto
the screen (magnification side imaging surface) 12 and forms an
image of light incident from the magnification side on the imaging
element.
The light valve modulates light from the light source and emits
modulated light. As an image display element that is used for the
light valve, any image display element, such as a liquid crystal
display element or a liquid crystal on silicon (LCOS) display
element, may be used. The light source may be appropriately
composed corresponding to a system of the image display element of
the light valve.
The imaging optical system comprises a first optical system G1 that
comprises at least one lens and is used in common in projection and
imaging, a second optical system G2 that comprises at least one
lens and is used only in projection, a third optical system G3 that
comprises at least one lens and is used only in imaging, and a
separation member S that separates an optical path from the second
optical system G2 toward the first optical system G1 from an
optical path from the first optical system G1 toward the third
optical system G3.
The first optical system G1 comprises a lens group L1.
The second optical system G2 comprises, in order from the
magnification side on the optical path, a lens group L2a, a
reflection member R, a lens group L2b, and an optical member PP
assumed to be a filter, a prism, or the like that is used in a
color synthesis unit or an illumination light separation unit.
The third optical system G3 comprises, in order from the
magnification side on the optical path, a lens group L3a and a lens
group L3b.
Each lens group in the first optical system G1, the second optical
system G2, and the third optical system G3 is not limited to a
configuration in which the lens group consists of a plurality of
lenses, and may have a configuration in which the lens group
consists of only one lens.
The separation member S reflects light from the second optical
system G2 toward the first optical system G1 and transmits light
from the first optical system G1 toward the third optical system
G3, and is composed of, for example, a transflective member, such
as a half mirror.
The separation member S is arranged on the most magnification side
among the reflection members in the imaging optical system. Here,
the "reflection members" mean members that reflect least 10% or
more of incident light. In the embodiment, the separation member S
and the reflection member R correspond to the reflection
members.
The imaging optical system is composed as described above, whereby
it is possible to secure the number of lenses (the lenses of the
first optical system G1 and the second optical system G2) to be
used in projection to provide high projection performance while
suppressing the number of lenses of the first optical system G1 to
be used in common in projection and imaging. Similarly, it is
possible to secure the number of lenses (the lenses of the first
optical system G1 and the third optical system G3) to be used in
imaging to provide high imaging performance.
The separation member S is arranged on the most magnification side
among the reflection members in the imaging optical system, whereby
it is possible to further reduce the number of lenses (the lenses
of the first optical system G1) to be also used in projection among
the lenses (the lenses of the first optical system G1 and the third
optical system G3) to be used in imaging, and the number of
reflective surfaces of projection light further decreases compared
to a case where the separation member S is not arranged on the most
magnification side among the reflection members in the imaging
optical system like the projection display device 3 according to
the third embodiment shown in FIG. 3. For this reason, it is
possible to further suppress reflected ghost.
In the projection display device 7 of the embodiment, it is
preferable that the first optical system G1, the separation member
S, and the third optical system G3 are arranged linearly such that
the separation member S reflects light on the optical path from the
second optical system G2 toward the first optical system G1 and
transmits light on the optical path from the first optical system
G1 toward the third optical system G3. During projection, since a
light source with high brightness is not needed, the configuration
of the image projection unit 11 to be used in projection is likely
to increase in size compared to the configuration of the imaging
element 10 to be used in imaging. For this reason, the first
optical system G1, the separation member S, and the third optical
system G3 to be used in imaging are arranged linearly, whereby the
total length of the device is easily suppressed. Therefore, it is
advantageous to reduce the size of the entire device.
For example, the separation member S that is composed of a
transflective member, such as a half mirror, generally has a
transflective reflective film formed on one surface of a
transparent substrate.
In the projection display device 7 of the embodiment, it is
preferable that, in a case where the member having the
transflective reflective film formed on one surface of the
transparent substrate is used as the separation member S, the
reflective film faces the first optical system G1, and the first
optical system G1, the separation member S, and the third optical
system G3 are arranged linearly such that the separation member S
reflects light on the optical path from the second optical system
G2 toward the first optical system G1 and transmits light on the
optical path from the first optical system G1 toward the third
optical system G3. Here, the transparent substrate means a
substrate that transmits 90% or more of light.
Since the thickness of the transparent substrate of the separation
member S cannot be completely eliminated, light that is transmitted
through the separation member S is slightly reflected by two
surfaces of an incidence surface and an emission surface of the
transparent substrate, and stray light may occur.
However, the separation member S is arranged such that the
reflective film faces the first optical system G1, whereby
projection light emitted from the image projection unit 11 is
reflected by the reflective film and is incident on the first
optical system G1 without being affected by the transparent
substrate of the separation member S. For this reason, projection
performance is not degraded due to the separation member S, and it
is possible to maintain high projection performance as the
projection display device.
It is preferable that an optical system consisting of the first
optical system G1 and the second optical system G2 to be used in
projection is a relay optical system that forms an intermediate
image MI. With such a configuration, it is possible to achieve a
wide angle with one eye. Furthermore, an optical system to be used
in projection is composed of a relay optical system, a reflection
member that bends the optical path is easily inserted into the
optical system, and a light beam on the projection display device
side in projection light emitted from the projection display device
can approach a horizontal state to a housing of the projection
display device. For this reason, it is possible to improve the
installability of the projection display device.
Even an optical system consisting of the first optical system G1
and the third optical system G3 to be used in imaging may be
composed of a relay optical system that forms the intermediate
image MI. With such a configuration, it is possible to achieve a
wide angle with one eye.
It is preferable that, in a case where at least one of the optical
system to be used in projection or the optical system to be used in
imaging is the relay optical system that forms the intermediate
image MI, the separation member S is arranged to be closer to the
magnification side than the intermediate image MI on the optical
path. With such a configuration, the number of lenses (the lenses
of the first optical system G1) to be used in projection among the
lenses (the lenses of the first optical system G1 and the third
optical system G3) to be used in imaging is reduced, and the number
of reflective surfaces of projection light decreases. For this
reason, it is possible to suppress reflected ghost.
Next, an eighth embodiment of a projection display device of the
invention will be described in detail referring to the drawings.
FIG. 8 is a schematic configuration diagram of a projection display
device according to the eighth embodiment of the invention. In FIG.
8, the screen 12 side becomes the magnification side in the optical
path order. In the embodiment, elements similar to the elements in
FIG. 7 are represented by the same reference numerals and
description thereof will not be repeated unless needed. Here, only
a difference will be primarily described.
As shown in FIG. 8, a projection display device 8 of the embodiment
is different from the projection display device 7 of the seventh
embodiment in that a reflection member R2 is arranged near a
position where the intermediate image MI is formed in the third
optical system G3 (between the lens group L3a and the lens group
L3b).
An optical system consisting of the first optical system G1 and the
third optical system G3 to be used in imaging is composed of a
relay optical system, whereby the reflection member R2 that bends
the optical path is easily inserted into the third optical system
G3. The reflection member R2 is inserted into the third optical
system G3, whereby it is possible to suppress the total length of
the third optical system G3 even in a case where the third optical
system G3 is designed with high performance to comprise multiple
lenses. For this reason, it is possible to achieve both of
performance and reduction in size of the projection display
device.
Even in the projection display device 8 of the embodiment, it is
possible to obtain the same effects as the projection display
device 7 of the seventh embodiment.
Next, a ninth embodiment of a projection display device of the
invention will be described in detail referring to the drawings.
FIG. 9 is a schematic configuration diagram of a projection display
device according to the ninth embodiment of the invention. In FIG.
9, the screen 12 side becomes the magnification side in the optical
path order. In the embodiment, elements similar to the elements in
FIG. 7 are represented by the same reference numerals and
description thereof will not be repeated unless needed. Here, only
a difference will be primarily described.
As shown in FIG. 9, a projection display device 9 of the embodiment
is different from the projection display device 7 of the seventh
embodiment in that a third optical system G3 consists of only a
lens group L3. In this way, the third optical system G3 may have a
simple configuration, and with such a configuration, reduction in
size of the projection display device is achieved.
Even in the projection display device 9 of the embodiment, it is
possible to obtain the same effects as the projection display
device 7 of the seventh embodiment.
Although embodiments of the projection display device of the
invention have been described above, the invention is not limited
to the embodiments.
For example, in the imaging optical system, in a case where an
optical system consisting of the first optical system and the
second optical system to be used in projection is a relay optical
system, the separation member may be arranged at the position of
the intermediate image on the optical path or the position adjacent
to the intermediate image on the optical path. Since a space is
easily secured near the intermediate image, with such a
configuration, the separation member is easily arranged.
As described above, in a case where the separation member is
arranged near the intermediate image, an optical system to be
closer to the magnification side than the intermediate image
becomes the first optical system. In a case where a relay optical
system is made to have high performance, since many lenses are
needed to be closer to the magnification side than the intermediate
image, the number of lenses of the first optical system G1 to be
used in common in projection and imaging increases. As a result,
since it is possible to suppress the number of lenses of the second
optical system to be used only in projection and the third optical
system to be used only in imaging, it is possible to achieve
reduction in size of the entire imaging optical system.
The light valve is not limited to an aspect in which light from the
light source is spatially modulated by the image display element
and is output as the optical image based on image data, and an
aspect in which light itself output from a self-luminous image
display element is output as an optical image based on image data.
As the self-luminous image display element, for example, an image
display element, in which light emitting elements, such as light
emitting diodes (LED) or organic light emitting diodes (OLED), are
arranged in a two-dimensional manner is exemplified.
In addition to those described above, various improvements or
modifications may be of course made without departing from the
spirit and scope of the invention.
EXPLANATION OF REFERENCES
1 to 9: projection display device 10: imaging element 11: image
projection unit 12: screen G1: first optical system G2: second
optical system G3: third optical system L1 to L3b: lens group MI:
intermediate image P, P1, P2: polarizer PP: optical member R, R1,
R2: reflection member S, SP: separation member W: quarter wave
plate
* * * * *